//
//  more.c
//  linux编程
//
//  Created by 黄辉 on 17/3/20.
//  Copyright © 2017年 黄辉. All rights reserved.
//

#include "more.h"
void do_more(FILE *fp)
{
    char line[LINELEN];
    int num_of_lines = 0;
    int see_more(FILE *),reply;
    FILE *fp_tty;
    fp_tty = fopen("/dev/tty", "r");
    if (fp_tty == NULL)
        exit(1);
    
    while (fgets(line, LINELEN, fp))
    {
        if (num_of_lines == PAGELEN)
        {
            reply = see_more(fp_tty);
            if (reply == 0)
                break;
                num_of_lines -= reply;
        }
        if (fputs(line, stderr) == EOF)
            exit(1);
        num_of_lines ++;
    }
}
int see_more(FILE *cmd)
{
    int c;
    printf("\33[7m more? \033[m");
    while ((c = getc(cmd)) != EOF) {
       
        if (c == 'q')
            return 0;
        if (c == ' ')
            return PAGELEN;
       
        if (c == '\n')
            return 1;
    }
    return 0;
}
